The Pakistani president, Pervez Musharraf, faced a barrage of criticism and threatened protests on Friday ahead of his arrival in London for a visit including talks with the prime minister, Gordon Brown. Human rights group Amnesty International plans a demonstration outside Downing Street on Saturday, while further protests are scheduled for Monday, the day Musharraf is due to with Brown.

Amnesty warned that Pakistan was facing a 'human rights crisis' which 'represents a serious threat to the political process in Pakistan' in a statement issued ahead of the visit. Musharraf was due to speak at think-tank the Royal United Services Institute on 'how he envisions the future of his country and the region' later Friday, its web site said.

His visit to London comes as part of a European tour which has also taken in the World Economic Forum in Davos, Switzerland. Throughout the trip, he has stressed that Pakistan's looming elections on February 18 will be transparent despite concern from critics, particularly after the assassination of opposition leader Benazir Bhutto on December 27.

Amnesty's country director for Britain Kate Allen said thousands of people had been detained without trial in recent months, adding that torture was common and the judiciary had been 'seriously undermined.' 'Against this backdrop, how can Pakistan have free and fair elections?' she asked. 'Gordon Brown must take this opportunity to demand that Musharraf's government bring to an end to the human rights violations that have characterised the recent period of Pakistan's history.'

In addition, nine distinguished figures from the world of law wrote to the Times newspaper on Friday calling for the urgent restoration of the rule of law in Pakistan.

Signatories included the heads of England's two most respected professional legal bodies — Andrew Holroyd, president of the Law Society of England and Wales and Timothy Dutton, chairman of the Bar Council of England and Wales.

They said Musharraf must respect the independence of the judiciary and release those lawyers currently detained, including former chief justice Iftikhar Chaudhry who is under house arrest.

Explaining the motivation for Monday's planned protest, human rights campaigner Peter Tatchell wrote in the Guardian newspaper: 'Gordon Brown's willingness to fete a despot like Musharraf is an insult to the millions of Pakistani people who oppose tyranny and yearn for democracy and human rights.'